Fig. 3. Investigation of energy dissipation based process.

a Emission spectra in the red channel of NaErF₄@NaYF₄@NaGdF₄:x%Yb@NaYF₄ UCNPs (x = 0, 10, 49, 80) with different shell composition. b, c Emissions spectra of NaErF₄@NaYF₄@NaGdF₄:49%Yb/y%Tm@NaYF₄ UCNPs (y = 0, 1, 5, 10). d Luminescence decay curves at 980 nm of the obtained UCNPs with different Tm³⁺ doping ratios under 980 nm excitation. λ_em emission wavelength. e Emissions spectra of NaErF₄@NaYF₄@NaGdF₄:x%Yb/1%Tm@NaYF₄ UCNPs (x = 10, 30, 50, 80). All of the UCNPs samples in these tests were dispersed in cyclohexane for the collection of spectra. Shell thickness is tuned around ~4 nm. λ_ex excitation wavelength. Power density is set at 45 mW/mm². f Diagrams illustrating the energy dissipation dominating process. Suppression of the inner core’s emission is substantially dominated by excitation energy dissipation, which can be enhanced through increasing energy transfer (ET) and subsequent energy consumption from emission or cross-relaxation (CR). Source data are provided as a Source Data file.